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Solar Power (Read 7394 times)
squiggle
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Re: Solar Power
Reply #17 - May 22nd, 2004, 12:04pm
 
Thanks. That was what I meant and you have confirmed my memory is not as faulty as I thought it was Smiley

Jon
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Lectrician
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Re: Solar Power
Reply #16 - May 22nd, 2004, 11:53am
 
if you mean, using 12 volt to power your house, via a Istep up transformer, then you are correct.  Lower the volts, and for the same load, the current will rise.

This is why the electricity boards do the exact opposite.  To combat the problems of volt drop associated with a large current flow, they up the volts to lower the current.

For example, a substation with an output rated at 1500amp, will only draw about 30amp from the 11, 000 volt primary side, when this load is placed on the national grid at 132,000 volt then the current is only going to be about 3 amp.
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Re: Solar Power
Reply #15 - May 22nd, 2004, 11:04am
 
Thanks for the extra info all. I'm sorry I somehow managed to loose trak of the thread.

FWL, no I hadn't considered that but it may make sense....

I've dropped my requirements in terms of thinking of powering the gringer/polisher that way in any case. I'd like to do a pond pump and maybe one or two low voltage lights in the BBQ area but even for that I seem to be coming up with a 21W panel and battery and charge controller and maybe around £500. (Of course I'm not an electrician and that estimate may be a mile out)

Weird though .. Free energy does seem to be quite expensive.

One other question. What sort of cables are needed for a larger installation, eg. to power a house. I seem to remember from school that W=I^2 R and its the current that needs the cable thickness. Also of course that W = IV. I'm sort of coming up with a notion that is we said a house was say 60A/240V, at 12V, we are looking at 1200A. This can't be right.

Jon
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« Last Edit: May 22nd, 2004, 11:07am by squiggle »  
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FWL_Engineer
Re: Solar Power
Reply #14 - May 7th, 2004, 10:59pm
 
Squiggle, have you considered Wind turbines?

There are small kits that can be bought for use on Boats that are not overtly expensive.
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Re: Solar Power
Reply #13 - May 7th, 2004, 10:47pm
 
Andrew..I should say your very sad for even being able to post that link..but damned it's funny!! Grin
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Re: Solar Power
Reply #12 - May 7th, 2004, 8:11pm
 
You reckon that hamsters can produce enough gas to cause a problem? Wink

Talking of hamsters, if you have a sound card.....

http://www.hampsterdance2.com/hampsterdance2.html

Andrew
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Re: Solar Power
Reply #11 - May 7th, 2004, 8:06pm
 
make sure there are no nacked flames present...you may not have a shed left to light up

ss
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« Last Edit: May 7th, 2004, 8:07pm by supersparky »  
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Re: Solar Power
Reply #10 - May 7th, 2004, 7:23pm
 
[quote author=Dewy  link=1083326756/0#9 date=1083953907]Try feeding them on baked beans for increased energy output of methane gas Wink [/quote]

Hell, they will be doing loop-the-loop in their exercise wheel! Wink

Andrew
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Re: Solar Power
Reply #9 - May 7th, 2004, 7:18pm
 
[quote author=HandyMac  link=1083326756/0#7 date=1083907122]Alternatively, get a cage full of hamsters and keep them fed - they could turn the paddle wheel. Getting constant velocity might be a bit of a problem though.....hamsters have a tendency to do a bit of exercise then go to sleep for a while.

Andrew
[/quote]
Try feeding them on baked beans for increased energy output of methane gas Wink
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Re: Solar Power
Reply #8 - May 7th, 2004, 6:35am
 
"Getting constant velocity might be a bit of a problem though.....hamsters have a tendency to do a bit of exercise then go to sleep for a while. "

'swhat the missus says about me.

Speaking of which... if you want to bone up on Solar this spanish site is quite interesting.

http://www.solener.com/index_e.html

It's a bit 'spanglish' in the translation but gives you some good info... also has a freebie calulator programme for mixed wind/solar systems.


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Re: Solar Power
Reply #7 - May 7th, 2004, 6:18am
 
[quote author=squiggle  link=1083326756/0#0 date=1083326756]we have a big pebble polisher that is never used. I think it's an induction motor - rated 0.25 bhp and 2.3A /240V. What would the feasability and cost be to run something like that in the summer months out there? I know I'd need an inverter..... [/quote]

Very simple mathematics rules this out as a no-no.

2.3A @ 240V is equivalent in power to 46A @ 12V )dividing the voltage by 20 requires the current to be multiplied by the same factor to get the same power rating), ignoring all sorts of things that have to be taken into consideration - inverter efficiency etc.

A regular car battery wouldn't be able to sustain that sort of drain for very long. Maybe an hour? Can't remember the figures for car batteries but I thought they quoted figures in the region of 50Ah.

And if you wanted to run the battery for 8 hours then you'd need a capacity of 8x46 = about 400Ah.

You can't get more energy out of the battery than you put into it in the first place, so during the day you'd need to be stuffing 400Ah in the direction of the battery. I don't know the figures for solar panels (I'll bow to FWL's superior knowledge on that detail), but mickey-mouse panels you can buy from Maplins for simple testing only produce a few mA's - and these panels cost a lot of money for just a few square inches.

What you could do with is a handy stream running by the side of the shed, then you might then just be able to put a paddle wheel in there to drive a small generator. Only problem is that I think government regulation would have something to say about extracting energy from the water supply (I don't know this for a fact).

Alternatively, get a cage full of hamsters and keep them fed - they could turn the paddle wheel. Getting constant velocity might be a bit of a problem though.....hamsters have a tendency to do a bit of exercise then go to sleep for a while.

Andrew
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Re: Solar Power
Reply #6 - May 7th, 2004, 3:14am
 
[quote author=squiggle  link=1083326756/0#3 date=1083370895]PS do you (or anyone else) see the cost of solar power coming down significantly in the near (say 10 yrs) future? [/quote]

The costs will come down, alot of the high cost is connected to the amount made, as with any product. However to make truly efficient Solar Cells is not cheap, it'll always be a trade-off.

I intend to have an entire section of the AE3 site dedicated to Renewable energy sources, so in the next month or so there should be some good information on there for you.
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Re: Solar Power
Reply #5 - May 1st, 2004, 3:18am
 
haha dewy LOL, grans got a set of them fingys, they dont give much light, more of a feature than a walk light, be better wit fkn ELV walk way lights  Roll Eyes
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Re: Solar Power
Reply #4 - May 1st, 2004, 2:59am
 
Solar powered garden lights have dropped dramatically in price.
They have loads in my local PO/newsagent/sweet shop at £2.99
They switch on automatically when it's dark & work up to 8 hours in the summer when we only have 4-5 hours of darkness. Grin
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Re: Solar Power
Reply #3 - May 1st, 2004, 1:21am
 
Thanks FWL.  It's even worse than I feared!!!

Jon

PS do you (or anyone else) see the cost of solar power coming down significantly in the near (say 10 yrs) future?
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Re: Solar Power
Reply #2 - May 1st, 2004, 1:10am
 
sqiggle, I would forget it, the cost is prohibitive. The kind of power that you would require to charge the batteries in an English winter day would require about 8sq meters of panel if you went for the high grade polycrystaline type, if you opted for the cheaper, less efficient types, then you would need about 10sq meters.

The solar panels alone would set you back at least £4K, plus you would need all the other infra-structure to go with it. Your project I would estimate, with putting a proper quote together, would set you back the best part of £10K.

It would be cheaper to run a cable out to the shed.
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Re: Solar Power
Reply #1 - Apr 30th, 2004, 5:41pm
 
the problem is keeping it running at night especially if there is a grey day or so

you would need a lot of batterys

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Solar Power
Apr 30th, 2004, 1:05pm
 
This one started with me wanting a pond pump about 30 metres from the house and on land we rent (it's part of a field next to the property). The easy solution would seem to be a solar kit but one idea leads to another...

Assuming we get the landowners permission, I could fit a solar panel to the roof of a shed we use which gets very good sunlight and I figure that I could charge a battery and not only run the pump but have some low volt lighting out there - perhaps nice when the hens are shut in or maybe even for a bbq if the sunlight is going down.

I think it's relatively easy to there but then I start thinking... we have a big pebble polisher that is never used. I think it's an induction motor - rated 0.25 bhp and 2.3A /240V. What would the feasability and cost be to run something like that in the summer months out there? I know I'd need an inverter but what else?  One thing with the polisher is when it's in use you don't want it stopping on a cycle which could be 2-3 days, otherwise you get a clogged mass of grit and stones.

It's a hair brained scheme, I know, one I don't think will ever be tried here, and one my guess is that would run into £thousands - far more than I'd be investing even if I had the money but I'm curious to see if anyone can propose a solution or ideas.

Jon
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